Process for manufacturing colloidal compounds of arsenic



Patented Feb. 16, 1926.

UNET STATES PATET FFlCE.1

AUGUST CHWALA, OF VIENNA, AUSTRIA, ASSIGNOR TO ODERBERGER CHEMISCHE WEBKE AKTIENGESELLSCHAFT OF ODERIBEBG, CZECHOSLOVAKIA, A JOINT 'STOCK COMPANY OF CZECHOSLOVAKIA.

PROCESS FOR MANUFACTURING COLI LOID AL COMPOUNDS OF ARSENIC.

No Drawing.

To all whom it may concern:

Be it known that I, AUGUST CHWALA, a citizen of the Republic of Austria, residing at Vienna, Austria, have invented certain new and useful Improvements in a Process for Manufacturing Colloidal Compounds of Arsenic, of which the following is a specification.

The present invention relates to the manufacture of colloidal compounds of arsenic and particularly of derivatives of arsenic acid and of arsenious acid. These compounds may be used in the form of a sol or of a gel preferably for destroying animal parasites of plants.

There exist known methods for bringing arsenate of lead obtained by mutual reaction of salts of arsenic acid and of lead-salts in the presence of protective colloids into a finely divided state, which methods consist in repeatedly treating the arsenate of lead formed in this manner in some liquid medium, to which a'protective colloid is added. This finely divided state, has been designated as semi-colloidal. Trials aiming at the production of true colloids by this method were not successful.

As to arsenate'of lead, obtained directly from the oxides of lead and other compounds of arsenic by the usual methods known at present, such as for instance arsenate of lime, there was prior to the present invention no possibility of reducing them to .a state of such fine dispersion as is necessary for obtaining homogenous solutions appropriate for application on plants by sprinkling.

Furthermore trials have been made which consisted in first reducing the reacting As a result of very exhaustive experi-- ments I have found that the reduction of arsenic compounds to a colloidal state by mere disintegration is not possible, not even in the presence of considerable quantities of protect ve colloids.

The present invention consistsof a'method for producing colloidal compoundsof Application filed August 20, 1924. Serial No. 733,222.

arsenic by mechanical dispersion in the presence of protective colloids, in which method the dispersion is carried out in the presence of free ions of metallic acids, that is to say in the presence of salts derived from higher oxides of a metal combining with oxygen in several proportions, the said oxides having the property of forming acids. As far as the principle is concerned, it is of no importance whether the free ions of metallic acids are added to' the liquid medium in the form of dissociated solutions or if compounds generating the said free ions-are formed in the solution itself by chemical reaction.

For transforming e. g. arsenate of lead, into the colloidal state the dispersion is initiated by the presence of small quantities of plumbate-ions, for instance by the presence of alkaline plumbates or particularly plumbates of earth'alkalies, but care is to betaken during this ste to have also free ions of lead in the reacting mass, although in small concentration, which result is reached by adjusting the concentration of the reacting mass to a certain degree.

Furthermore I have found that the transformation into the colloidal state is favourably influenced by the addition of high molecular weight compounds having the tendency of forming complex compounds or adsor hon-compounds, no matter if these additions are of organic or inorganic nature.

The following compounds have been found to be particularly effective when used as additions forpromoting the transformation of arsenic compounds into the colloidal state. by means of metallic acid ions, viz: inorganic compounds of silicon, arsenic and antimony, stannate of potassium, salts of molybdic acid, salts of several aliphatic or aromatic acids, such as for instance succinate of sodium, malonate of zinc and metastannic acid.

Also sulphides and thionates roduce a similar effect, but they have the raw-back, that the final product contains small quantities of lead sulphide, the generation of whichis due to the dissociated lead-ions, and owing to which the arsenate of lead finall assumes a dark colour and an -'unsi ht y aspect.

lhedispersing qualitiesof the metallic A, As A 3000 parts by weight of a paste of leadarsenate obtained by the known method and containing about of water are dispersed in one of the known mechanical de vices with 50 parts by weight of calcium plumbate'suspended in 100 parts of water, and with 800 parts by weight of a 20% solution ofthe sodium salt of protalbinic acid,

or, instead of the latter, with waste sulfite' liquor. Then the second reagent is added, consisting of 50 parts by weight of an aqueous suspension of calcium plumbate, the

addition being effected very slowly and gradually at intervals. After intimate mixing by agitating and stirring the third reagent is added, viz, 10 parts by Weight of sodium antimoniate, intense mixing and stirring being continued until a small" test quantity of the mass, when poured into water, forms a perfectly homogenous and durable milk.

The product thus obtained is a uniform colloid. It does not deposit a sediment in the flocculometer with two branches of Wolfgang Ostwald and Hahn (Kolloid-Zeitschrift 30, 62, 1922), it is readily coagulated by anyone of the electrolytes, does not penetrate through an animal membrane by diffusion and shows in-the ultra-microscope the characteristic movement called the Brown ian movement. It therefore proves to be in fact a perfect true colloid.

This product also shows the appreciable property of constituting a reversible gel. Total dehydration will destroy the colloidal state. But if the product is dried at low temperatures, say under 40 centigrade to such degree, that it still contains a small amount of water, it remains after the drying colloidally soluble in water.

In the same manner Schweinfurt-green having the formula for instance by addition of the so-called Fehlings solution.

The colloidal arsenic compounds thus manufactured are homogenous preparations readily and perfectly wetting the plants and are used for destroying the animal parasites an acid with an equivalent of a base joined by the ordinary (principal or normal) valencies are understood, but also all other compounds, particularly those of complex nature, which are not combined in the ratio of the principal or normal valencies, but

areconnected to larger molecules by residual aflinity or by additional (auxiliary) valencies. The term compounds of complex nature has been usedto include not only the compounds in the strict sense of this word but also the so-called adsorption compounds.

lVhat I claim is:

- 1. In the art of producing colloidal compounds of arsenic the step which consists in mechanically dispersing the arsenic compound in presence of protective colloids and of salts of metallic acids derived from higher oxides of a metal combining with oxygen in several proportions, the said oxides: havin the property of formin acids.

2. In the art of D ically dispersing the arsenic compound in presence of protective colloids and of salt of a metallic acid.

3. In the art oi producing colloidal compounds the step which consists in mechanically dispersing the arsenic compound in presence of protective colloids and of salts of plumbic acid.

4. In the art of producing colloidal compounds the step which consists in' mechanically dispersing the arsenic compound in presence of protective colloids and of salts of lumbic acid with addition of compounds of high molecular weight having the property of forming compounds of complex nature with insoluble arsenic compounds.

5. In the art of producing colloidal compounds the step which consists in mechanically dispersing the arsenic compound. in presence of protective colloids and of salts of alkaline earths and of plumbic acid with addition of compounds of high molecular weight having the property of forming compounds of complex nature with insoluble arsenic compounds.

6. In the art of producing colloidalcompounds the step which consists in mechanically dispersing the arsenic compound in presence of protective colloidS and of calroducing colloidal compounds the step w ich consists in mechancium plumbate with addition of compounds of high molecular weight having the prop.- erty of forming compounds of complex na' ture with insoluble arsenic-compounds.

7 In the art of producingcolloidal compounds the step which consists in mechanically dispersing the arsenic compound in presence of protectivecolloids and of salts of lumbic acid with addition of compounds of liigh molecular weight having. the property of forming compounds of comple'x nature with insoluble arsenic compounds the additions being effected successively.

8. In the art of producing colloidal compounds the step which consists in mechanically dispersing the arsenic compound in presence of protective colloids and of salts of plumbic acid with addition of com pounds of high molecular weight having the property of forming compounds of com- )lex nature with insoluble arsenic compounds the additions being effected successively and alternately.

9. In the art of roducing colloidal compounds the step wiiich consists of mechanically dispersing the arsenic compounds in presence of protective colloids and of calciuan plumbate with additions of protalbinic aci 10. In the art of producing colloidal com- 'ounds the step which consists in mechancally dispersing the arsenic compounds in presence of protective colloids and of calcium plumbate with additions of protalbinic acid and of antimoniate of-sodium.

l1. Preparations for the protection of plants (for destroying the animal parasites of plants) consisting of a colloidal compound of arsenic, protective colloids and of salts of metallic acids derived from higher oxides of a metal combining with oxygen in several proportions, the said oxides having the property of forming acids.

12. Preparation for protecting plants consistingof a colloidal arsenic com ound, of protective colloids and of salts o metallic acids.

13. Preparations for protecting plants consisting of a colloidal arsenic compound, of protective colloids, saltsof plumbic acid and compounds of hi h molecular weight having the property 0? forming compounds of complex nature with insoluble arsenic compounds.

14. Preparation for protecting plants consisting of a colloidal arsenic compound, pro-v tective colloids, lumbate of calcium and compounds of bi molecular weight having the property of orming compounds of complex nature with insoluble arsenic compounds.

15. Preparation for protecting plants consisting of a colloidal arsenic compound, protective colloids, calcium plumbate and protalbinic acid.

16. Preparation for protecting plants consisting of a colloidal arsenic compound, protective colloids, calcium plumbate, protal binic acid and antimoniate of sodium.

In testimony whereof I have afiixed my signature.

- AUGUST CI-IWALA. 

